Painting Buttercream Question

I've been battling just to get CC to load for quite some time so I'm pretty happy it's finally up for me. I did attempt to do a search but it's just not happening for me tonight. Then I had written this whole post and was in the process of loading a picture but cyberspace ate the whole thing so this is the stripped down version!

My basic question is can I paint on buttercream? I am doing a cake that will be frosted in a shade of green then have a darker green buttercream piped over the top of that in the design areas. Before I pipe the dark green I would like to paint a kind of gold/tan type color onto the lighter green.

I wish I could get the picture to load but between me being on dial up and the upgrading of CC it's just not going to work. In the picture the gold/tan color is writing that kind of blends into the background. I think if I were to try to pipe this on as well as the dark green it would just end up looking busy instead of how the picture looks. It's a logo for my church and I'm doing the anniversary cake so I'd really like to make it work if I can.

So, if I can paint on the buttercream, how do I do it? Should I refrigerate or freeze the cake to get a nice firm frosting? Mix gel or powdered colors with vodka or something? Which would be better or should I use something else? Please help! TIA.

When I paint on buttercream I make sure it's got a nice solid crust but I do not refrigerate it, you do not want to risk it "sweating' and having your work drip and bead up. I always use almond extract to slightly water down icing colors like water color. I tried vodka and hated it. I like the smell and taste of almond extract and the fact that it evaporates so well, but lots of people on CC love lemon extract. The biggest problem I have is with the texture or the buttercream, it has to be super smooth or you will really see the "paint" well up in the texture on the icing. I just had that problem on a cake and could have kicked myself! Good luck, I really enjoy painting on buttercream.

Thank you so much for the help! Do you use gel colors when you paint? My husband's birthday is the week before this cake is due so I will be practicing on his first (he doesn't care what it looks like so long as it tastes good. )

Thanks for the tips about sweating, that thought never even crossed my mind. Do you think the flavor of the extract matters as long as it's clear? Does it need to be alcohol based? The cake will be a strawberry/vanilla flavor combo and I'm not sure how the almond would go with that.

I've used both Wilton and Americolor and they both work great. I bought a $1 paint pallette with the little wells and a lid at Hobby Lobby and it's nice because you can mix up a whole pallette and when they dry out you can just store them and re-wet them later. (they also look exactly like watercolor on dried RI for sugar cookies too, so don't woarry about wasting it, you'll find a use) I would say it probably doesn't matter what kind of extract you use as long as it's alcohol based. The big difference is probably the evaporation time, and it makes me nuts if it takes forever to dry, but that's a personal issue